The studies are designed to provide information about 1) factors regulating hypothalamic corticotropin releasing factor (CRF) content and secretion, 2) the possible functional relationship between the pituitary and adjacent CSF compartments with special attention to ACTH, and 3) factors regulating ACTH secretion in man and the rat. BIBLIOGRAPHIC REFERENCES: Cook DM, Kendall JW, Allen JP and Lagerquist LG: Diurnal variation and dexamethasone suppressibility of plasma ACTH in various stages of Cushing's disease. Clin Endocrin 1976 (in press). Kendall JW, Gray DK and Gaudette ND: Corticotropin releasing factor (CRF) activity in rat plasma. Proc Soc Exp Biol Med 1976 (in press).